Conventionally, devices such as televisions, PC monitors, mobile phones, smart phones, portable game devices, tablet devices, wearable devices and automotive monitors, among others, have used a liquid crystal display device or an organic EL panel as a display means. In recent years, in such display devices, in view of finer pitches and thinner and lighter devices, methods using anisotropic conductive film (ACF) have been employed in which a driver IC is directly mounted onto a glass substrate of a display panel or in which a flexible substrate on which, for example, a driver IC has been formed, is directly mounted to a glass substrate.
On the glass substrate to which the IC or flexible substrate is to be mounted, a plurality of transparent electrodes comprising ITO (indium tin oxide) are formed and the electronic component such as an IC or flexible substrate are connected onto these transparent electrodes. The electronic component to be connected onto the glass substrate has electrode terminals corresponding to the transparent electrodes formed onto the mounting surface thereof and is thermocompression-bonded onto the glass substrate via an anisotropic conductive film, thereby connecting the electrode terminals to the transparent electrodes.
The anisotropic conductive film contains a binder resin into which conductive particles are dispersed and is film-formed, and by being thermocompression-bonded between two conductors, electrical conduction between the conductors is achieved by the conductive particles and mechanical connection between the conductors is ensured between the conductors by the binder resin. The adhesive constituting the anisotropic conductive film, although typically a highly reliable thermosetting binder resin is used, may be a photosetting binder resin or a thermo/photosetting binder resin.
In the case of connecting the electronic component to the transparent electrodes via such an anisotropic conductive film, the anisotropic conductive film is first temporarily bonded onto the transparent electrodes of the glass substrate by a temporary pressure bonding means which is not illustrated in the drawings. After mounting the electronic component onto the transparent substrate via the anisotropic conductive film to form a temporary connection body, a thermocompression bonding means, for example, a thermocompression bonding head, is used to hot-press the electronic component along with the anisotropic conductive film towards the transparent substrate. Heat applied by the thermocompression bonding head causes a thermosetting reaction in the anisotropic conductive film, thereby connecting the electronic component onto the transparent electrodes.